Underside of Sunbrella bimini showing stains/spot

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Gary13035

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A slip mate got new canvas last year and they get dark spots and stains that appear on the underside of the fabric. It cleans off with a damp cloth but returns a week later.

I think it could be mildew, not sure.

Does anyone else have a similar problem and do they have a method to keep the fabric clean for a longer stretch of time?
 
Mildew. Yup. Vinegar seems to work. Anything else we've tried bleaches or darkens the material.
 
If the top is made from sunbrella fabric check out the sunbrella website...They give methods for cleaning...I had the same thing on my boat and took their advice on using a bleach soap mixture and the top came up looking like new...

http://www.sunbrella.com/na/en/marine.pl
Click on Care and Cleaning
 
Carver,

Their bimini looks like new after washes the mildew off, but it returns weekly. Does the Sunbrella treatment you used stop the mildew from coming back for a while?
 
You have to kill the mildew living in the material.Mild bleach solution or commercially available mildew remover. Simple washing only removes it from the surface and leaves spores behind to continue growth in the humid air.
 
quote:
Originally posted by Gary13035

Carver,

Their bimini looks like new after washes the mildew off, but it returns weekly. Does the Sunbrella treatment you used stop the mildew from coming back for a while?

Click to expand...


The mildew stays away, but be sure to treat the canvas with the sunbrella reccommended 303 after washing...
 
sublimetime has it right - you have to kill the stuff in the fabric. Mildew feeds not on the fabric but on the organic matter (dirt) trapped in the fabric. Soak it using bleach following Sunbrella's instructions on their website.

There can be one complicating factor. If the material is the vinyl-backed product (like Seamark) the vinyl coating traps dirt and makes it hard to get all of it. It's like having a shower curtain applied to the inside of your canvas.
 
I have a front bimini made from seamark(dark navy blue). This top gets the mildew on the inside during high humidity. I just wet a magic eraser and wipe one pass on the inside eevery inch of it.mildew dissappears before your eyes and stays away about 4-5 weeks. No colorafst problems at all.
 
It's the mildew on the other side of the coating from trapped dirt in the fabric that's the problem. Soaking with an oxygen bleach works.
 
I'm havng the same problem. Just washed on the dock - no good. Then washed in the clothes washer with bleach .. a bit better. Not perfect, given it is a light beige color abd shows everything.

Funny you should mention shower curtains... On my old boat, it had cheaper vinyl-backed canvas with mildew. I simply sprayed Tilex once in a while directly onto the mildew, and it went away. The vinyl was garbage after 5 years, though I'm not sure the Tilex had anything to do with it.
 
I find that just wiping it with bleach only gets the surface. You have to soak or spray it in order to get deep into the fabric. Doesn't need to be straight bleach, a little diluted works fine but a couple of safety cautions.... be sure to wear eye safety if you are spraying or wiping above you. Bleach and eyeballs do not get along. Also, be sure, especially if spraying, that you cover any items that might be bleached out by overspray or drops. It may not show up on clothes until they hit the washer.. much like battery acid... it seems to attack later. But I agree with using 303 afterwards. It will help protect and restore any oils taken out by the bleach.
 
Gary,

One section of my canvas is the sunbrella seamark material and the other section is standard sunbrella. The seamark section developed mold/mildew spots midway through last season.

A dockmate suggested that I try a 50/50 solution of hydrogen peroxide and water, which I did. It eliminated the mold/mildew for the balance of the season. You don't have to scrub the surface of all mold/mildew when applying the solution. When it drys, the mold/mildew will disappear.

Bob
 
I have dark (Black Cherry) Sunbrella and the mildew shows as light colored spots. I get it on the inside of the fabric during the winter. Short of cleaning, I found that a good vacuuming with a floor brush attatchment gets rid of it all. I'll vacuum it a couple of times during the winter. It's too dry around here during the summer to have the problem.
 
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